I apologise for the theological sounding question, but I couldn't phrase it any better.
In Oyasumi PunPun, PunPun can see God whenever he chants 'Dear God, dear God, tinkle-tinkle hoy'
This character always has the same expression and is realistic to a point that it seems it has been copied from a photograph or similar media.
Is God based on the appearance of the mangaka or anyone in particular?